You can get a pretty basic version of Epocrates online (for free, I believe). I used this first (and still have it on my PDA) to see how much I would really use a drug guide while in school.
My #1 suggestion, though is from Lexi-Comp --- Dental Lexi Drugs. I find it more useful than other drug programs that are geared toward med students, physicians, etc.. because it has specific info for each drug regarding "Effects on Dental Treatment" and "Vasoconstrictor/Local Anesthetic Precautions". The program has versions for both Palm and Windows.
